1. Field of the Invention
The invention concerns the use of a brass alloy with a high degree of cold workability for sanitary pipes. In the present context sanitary pipes are those which are used preferably in a domestic situation in the first stage of disposing of waste water or sewage, more specifically in the trap region. They involve thin-wall pipes of about 0.4-1 mm wall thickness which, in accordance with their use as components which in part are severely curved, must have a high level of bendability, that is to say cold shapeability. The pipes must have a good surface and must be chromium-plateable.
2. Discussion of the Prior Art
Hitherto brasses of the composition Cu 63, Zn 37--referred for the sake of brevity as MS 63--with a high level of purity are used for such sanitary pipes. Those brasses have the above-mentioned advantageous properties and in particular very good cold-shapeability, but they are very expensive. That is due in particular to the fact that there is no scrap or waste return for re-use. As MS 63 is used essentially only for processing involving shape-changing procedures and is not employed for cutting machining procedures, such scrap also scarcely occurs. Therefore a noticeable reduction in price in connection with sanitary pipes can be achieved only if an alloy is found, which contains cheap scrap materials and which nonetheless can be satisfactorily cold-shaped.
The wide-spread so-called machining brasses, namely those which can be subjected to cutting machining on automatic machines have a copper content of about 58-60%. They are very inexpensive as there is a large scrap circulation, both nationally and internationally. Those brasses have a content of about 2-4% lead and possibly iron as an impurity. Such scrap materials are therefore not suitable for the production of the high-purity MS 63-brasses.